This issue of GPSolo's Technology & Practice Guide focuses on planning for and recovering from disaster. For us road warrior types who seldom leave home without a laptop computer, a common form of "disaster" is the gut-wrenching sound of metal or plastic splintering against a hard surface as another computer bites the dust. Although laptop computer manufacturers have dramatically improved the laptop's ability to survive a minor impact, the fact remains that computers get seriously damaged every day due to carelessness, malice, and simple bad luck.There is not much that you can do to prevent damage to an unprotected computer that falls or is knocked to the ground. But you can minimize the risk to your laptop computer by investing in a well-built protective computer bag. Of course, buying a bag doesn't solve the problem by itself-using it properly is the next step. A friend diligently packed her new laptop into its expensive protective case, put the case in the back seat, arrived at her destination, and pulled the case out of the back seat-only to watch openmouthed as her computer bounced to the pavement. Amazingly, the computer still works. (In case you are interested in the brand of this damage-resistant computer, it is a Winbook X2, www.winbook.com.)The moral of this story is that it is never enough to have the means available to prevent disaster. You must actually use the means. Don't count on being as lucky as my friend was.

When it comes to computer bags, beauty rests in the beholder's eye, and one person's idea of a "perfect" case may not suit another user at all. Following are suggestions to help you choose a computer bag that will serve you well. As those of you who regularly read this column know, I have worked as a road warrior for a while, carrying laptop computers with me for at least the last dozen years. I don't claim the largest collection of computer bags this side of a large luggage store, but I likely come close. I have tried almost every conceivable kind and configuration of computer bag; my wife and children have complained that I cannot pass a luggage store without stopping to check out the computer bags, vainly searching for the holiest of grails, the perfect computer bag. Although I have not yet found the perfect computer bag, I have found some pretty good ones that will suffice while my quest continues.Computer bags come in a variety of styles. The easiest category to discern is those that have wheels and those that do not. Next, wheeled bags separate into those that double as suitcases and those that serve only as computer briefcases. Non-wheeled bags come in a variety of configurations, generally classifiable as backpacks, shoulder bags, traditional briefcase bags, and envelopes or computer sleeves. The categories tend to blur somewhat now that many of the bags convert to multiple carrying styles. I have some bags that come with a carry handle, a shoulder strap, and a backpack conversion strap and include a removable sleeve that often functions as a separate small computer bag. Victorinox/Swiss Army (www.swissarmy.com), maker of the famous multi-tooled Swiss Army knives), emphasizes convertible bags in its offerings. Most of its computer bags include a carrying handle, shoulder strap, backpack conversion kit, and removable computer sleeve/separate computer bag. Many versions also come with wheels.

What makes a good computer bag? The most important quality is protection for the computer. No matter how nice it looks, if it fails to adequately protect the computer, it has little value to you. Computer "protection" comes from low- and high-density materials in varying degrees of thickness and from special slings that absorb the shock if a case drops to the ground. All padding provides some protection. High-density foam provides adequate protection from a relatively thin layer. Lower density materials require thicker applications, making them bulkier and more space consuming. Watching people regularly abuse their computers by dropping the bags six to ten inches to the floor has convinced me that shock-absorbing slings and extra padding are worthwhile additional protections.Many cases contain a removable computer envelope or sleeve that protects the computer inside the case and, in many instances, can serve as a small computer carrier on its own. Envelopes (generally available separately) also allow you to use a case not specifically designed for computers. In judging sleeves, look for a secure fastener to ensure that the computer does not fall out of the case, adequate protection and padding for the computer, and a handle or attachment for a shoulder strap. The shoulder strap option makes the sleeve more useful and is safer for the computer. Additional pockets to store a few essentials are a nice bonus.

The Inside StuffTo assess the construction of the bag (and each of its parts), think in terms of good luggage or a good briefcase. Check for well-stitched seams and a sturdy, strong, and comfortable handle, preferably one with some padding. If the bag has a shoulder strap, be sure it has secure attachment hardware and a comfortable strap. Most people find wider straps more comfortable because they better distribute the load. The most comfortable shoulder straps have flexible, wider padding in the center to protect the shoulder, are ergonomically designed to fit securely over the shoulder, and are backed with anti-slip material to minimize movement.

Don't buy a computer bag unless you have your computer (or at least accurate measurements for your computer) with you, so you can check its fit in the protective padding. Many of the large-screen computers will not fit in older bags designed for earlier models. Most sleeves and padded sections accommodate fairly deep computers; if you have a thinner laptop, the sleeve will not fit snugly. In most cases, that is not a major problem, but do not succumb to the tendency to stuff additional gear in the extra space, leaving you with no padding between it and the computer.If the bag functions as a backpack, be sure to try it on. Make sure that the loaded pack fits your body comfortably. One size does not fit all! Be particularly careful with wheeled cases that convert to backpacks because the handle and wheel mechanism generally rest against your back in the pack configuration. Check the straps for fit and comfort. Wide, well-padded straps offer the most comfort and utility. Look for strong, reliable closure connections on the bag and for solid hardware connecting the straps to the bag.

You probably will use the extendable handle on a wheeled bag more often than any other carrying mechanism. Be sure it is strong, well built, and comfortable to use. A handle mounted on the exterior provides maximum interior storage space, but an interior mount gives a more finished look. Most extending handles are supported by two rods joined at the top by the handle; some bags (notably parts of the Swiss Army collection) come with only a single rod connecting the handle to the bag. Although the single-rod handle looks pretty neat, if you plan to add a second case or anything else on top of the computer case as you roll it along, a single rod will prove unstable.Bags with a wide wheel base roll more smoothly and are less likely to become unbalanced when they hit a bump than bags with a narrow wheel base. Larger wheels (within reason) also work better than smaller wheels. Inline skate-type wheels are my favorites because they roll easily and can easily be replaced. Some of the new bags have retractable wheels, which are a mixed blessing. On one hand, dirt from the wheels won't get on your clothing if you carry the bag; but on the other hand, the retractable feature is one more thing that can go wrong. A jammed set of retractable wheels effectively means carrying the bag. Additionally, retractable wheels generally run small to facilitate the mechanics of retraction.

Storage. Many of us don't hit the road without taking all the comforts of modern home technology with us (the "Gear"). This can include a computer, connecting cables, electric plugs, a DC adaptor, one or more drives and connecting cables, a Palm device or equivalent, a mobile telephone, a pager, chargers and additional cables for the Palm device and the mobile phone, a pair of glasses or two, and an assortment of disks for backup, storage, entertainment, and emergency use. We also need some files, possibly some other reading material, a few pens, and paper. We might also include a digital camera, a digital recorder, and other miscellaneous items like a portable projector. (They come small enough these days that you can reasonably think about packing it in the same bag with your computer.) The well-designed computer bag will provide reasonable accommodations for all the Gear.Many bags include a front section with pockets for business cards, a Palm device, glasses, mobile phone, pager, pens and pencils, and an assortment of other odds and ends. Personally, I like that type of design. Everything is neatly ordered and readily available. I generally store my small digital camera and a recorder there as well. Of course, a section that accommodates legal-sized files is a must. I like bags that store the computer in the center of the case, on the theory that my gear and files offer additional protection to the laptop. The back is the next best alternative. Carrying the computer in the front of the bag makes it unbalanced and less comfortable to carry. With backpacks, the computer should always be in the back part of the case (the part nearest your back when you carry it). I greatly prefer the convenience and versatility of a removable sleeve to padding mounted inside the case.Materials. Bags come in leather, cordura nylon and other artificial materials, and imitation leathers. You also can find hard-shell cases for maximum protection. Although I love the look and feel of real leather, most of my bags are heavyweight cordura nylon, which is water-resistant, wears even better than leather, and is relatively impervious to damage. Using a case that doesn't advertise "computer on board" may be safer, but don't trade good protection for camouflage.

Price. Computer cases, like briefcases, are available from under $100 to whatever you are willing to pay. Leather costs more than the same bag in nylon. None of the bags discussed in this article costs more than $500, and you can find most for less than $400. If you shop around, particularly online, you can find some exceptional values. Some discounts for closeouts of discontinued items may particularly appeal to you, but you may not want to order a bag you haven't tried first. Fit and feel are especially important for backpacks. Be sure to verify that the bag will accommodate your laptop before you order it.

Getting Down to CasesIn my opinion, the two best lines of cases are Brenthaven (www.brenthaven.com) line and Victorinox/Swiss Army (www.swissarmy.com) line, with Brenthaven the winner by a slight margin. Both manufacturers build attractive, well-designed, rugged cases that provide substantial protection to your computers.Some comparative facts:

1. Cost. Brenthaven's cases list in the $130-$400 range for nylon; Swiss Army, $185-$425. Swiss Army also has a more expensive larger case in its eMotion line.

3. Sleeves. Both manufacturers include removable computer sleeves in their bags, but Swiss Army's readily converts to a smaller shoulder bag with good vertical drop protection and strong side-support construction. Brent-haven's sleeve is virtually useless as a separate bag because it has no fixed form and no way to carry it other than under your arm. Brenthaven, however, makes a small piece, the Computer Glove ($129 list) that I often use in lieu of the bag sleeve. The Glove has pockets for additional items and a full cover that the Swiss Army piece lacks. But everything's a tradeoff: The Swiss Army piece has better vertical drop protection.

4. Carrying systems. Both companies provide comfortable shoulder straps, but Brenthaven has the most comfortable carry handles around. Swiss Army offers a number of backpacks, bags, and conversions.

6. Design. Both manufacturers use the interior retracting handle design, and both make excellent use of the space around the extending handle, creating separate zippered pockets on each side. Swiss Army even includes a removable zippered pouch in some of its bags for cords, cables, or miscellaneous connectors that might otherwise easily get lost. Both companies have given obvious thought to creating pockets for files, cards, pens, disks, and the other paraphernalia that you will want to carry.

7. Appearance. Both lines have very distinctive appearances and are easily identified by an experienced eye. The Swiss Army pieces, however, look much like its regular luggage line, which offers some camouflage.Brenthaven makes three wheeled bags: the Mobile Topload, Mobile Brief, and Mobile Urban (largest to smallest). The two smaller bags list for $379 and the largest for $399. The Mobile Topload makes a knockout large bag and is my favorite in that range. I have packed it with two laptops, and with a laptop, a projector, the rest of the Gear, and files, and had room to spare. (You may have some difficulty getting the fully packed Topload under airplane seats or in some overhead bins.) The Mobile Urban bag seems to fit everywhere but has a very narrow wheelbase and can be less stable when rolled over bumps.

Brenthaven's non-wheeled bags all look similar from the outside, but the differences are apparent on closer examination: larger capacities, expansion capabilities, and varying numbers of pockets and compartments. The Topload is an excellent choice for a medium-sized bag. It holds a computer and the Gear with no problem and easily fits under a plane seat. It lists for $279 in nylon and $449 in leather.

Swiss Army's WebPack and Web Mobilizer are my favorite pieces from the Swiss Army line. Both come with the removable cross suspension computer sleeve. The WebPack lists for $225 and the Web Mobilizer for $365. The WebPack also converts to a shoulder bag or backpack. The Web Mobilizer has retractable wheels. Swiss Army also makes a WebPack Plus that offers retractable wheels ($365 list).

SleevesIn addition to the Brenthaven Glove and the Swiss Army cross suspension sleeve, you can find a number of other good sleeves. Two pieces that deserve your attention are made by Trager (www.Tragerusa.com): the TransPorter and the Executive TransPorter. At list prices of $45 and $60, respectively, these small bags may well be the best buy around. The TransPorter has hard-shell sides to protect the computer and extra-thick foam at the bottom of the bag to minimize the risk of damage from a vertical drop. Both double as sleeves. The TransPorter has two open pockets but no shoulder strap; the Executive has a zippered cell phone pocket, a zippered organizer pocket, and a shoulder strap. Both bags provide exceptional protection for your laptop and will easily fit within other types of bags to enable you to carry your laptop securely.Trager provides protection ratings for its bags, and both of these rate 90, Trager's highest. Trager also makes a series of backpacks and briefcases that look like they belong on campus rather than in a law office, which could also provide some camouflage.

BackpacksIf you want an authentic backpack case (not a convertible), check out Tom Bihn (www.tombihn.com). Its ultimate computer backpack consists of four parts: the Brain Bag, which is a backpack shell ($130); the Snake Charmer, a case for cords and small parts that fits into the Brain Bag ($20); the Brain Cell computer sleeve ($50); and the Freudian Slip, an amazingly clever insert that efficiently holds papers, files, pens, and a variety of other devices ($35). You can get any combination of components, but the package is so good, you will want it all.One word of caution: I was warned twice on a recent United Airlines flight that new regulations preclude counting a backpack as your "personal item" for carry-on purposes-it will be considered luggage. Bags that look like something else but double as a backpack will still pass muster as a personal item-a clear case of form over substance!

Special CasesTwo unique bags deserve special mention: Shaun Jackson Design's lapdog and Back Office (www.sjdesign.com). Priced at $139 and $149 respectively, they offer reasonable protection for the computer and open on your lap to a miniature office workspace, including pockets for cell phones, Palm devices, pagers, etc. The lapdog folds over the computer and is a shoulder bag, while the Back Office also converts into a backpack.

Final TipsI would like to leave you with a few thoughts about using computer bags. Many people have a tendency to walk into a room and drop their briefcase from three to eight inches above the floor. Don't do that with a loaded computer case! And don't drag wheeled computer bags up stairs or off curbs! Finally, you can pull a wheeled bag by using an underhand or overhand grip. Over the handle offers less support and can result in dropping the bag when it rolls over a bump or uneven surface.

Jeffrey Allen is the principal in the Graves & Allen law firm in Oakland, California. A frequent speaker on technology topics, he is the special issue editor of GPSolo's Technology & Practice Guide and editor-in-chief of the Technology eReport.